<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
  <div th:fragment="header">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" th:href="@{/css/bootstrap.min.css}">
    <script th:src="@{/js/jquery-3.2.1.min.js}"></script>
    <script th:src="@{/js/bootstrap.min.js}"></script>
  </div>
</body>
</html>